I put together the 1.21.0rc1 this afternoon. I'll announce it shortly, but, first, some observations.
* When you add or remove a configuration variable, it should have release notes. When you update the release notes, please make sure that you also update MW.o. A number of variables are mentioned in the release notes that don't have a corresponding page on MW.o. The following configuration variables are the currently redlinked on https://www.mediawiki.org/wiki/Release_notes/1.21. If you can update their on-wiki documentation, I (and I'm sure others) would appreciate it. ** $wgBug34832TransitionalRollback ** $wgEnableCanonicalServerLink ** $wgPageInfoTransclusionLimit ** $wgMaxShellWallClockTime ** $wgShellCgroup ** $wgSquidPurgeUseHostHeader ** $wgDebugAPI ** $wgAPIGeneratorModules
* Should the breaking changes be consolidated to a single section of the release notes? Right now, they are in three different sections. I think they should be moved to the top of their section at the very least (I did this on-wiki).
* There remains one pending change that is not in the 1.21 release candidate -- "Password Recovery system uses Tokens" -- because it hasn't been merged into core yet. This change will probably have to wait until 1.22, but I'll leave it on https://www.mediawiki.org/wiki/MediaWiki_1.21 for now.